Ore-concentrating table



B. A. HUGHES.

ORE CONCENTRATING TABLE.

Patented June 15, 1920.

2 SHEETS-SHEET 1.

awuwnt a E5. H. HUGHES B. -A. HUGHES. v ORE CONCENTRATING TABLE.APPLICATION FILED MAR. 17, I917. RENEWED MAR. 22, I920- Patented June15, 1920.

2 SHEETS-SHEET 2.

ESSS Eg amen 601 5. Fl. HUGHES NIT ORE-CONCENTRATING TABLE.

Specification of Letters Patent. Patented June 15, 1920.

Application filed March 17 1917, Serial No. 155,539. Renewed March 22,1920. Serial No. 367,828.

To all whom it may concern:

Be it known that I, BENJAMIN A. HUGHEs,

a citizen of the United States, residing at Colorado Springs, in thecounty of El laso and State of Colorado, have invented certain new anduseful Improvements in Ure- Goncentrating Tables, of which the followingis a specification, reference being had to the accompanying drawings.

This invention relates to ore concentrating tables of the reciprocatingtype, and particularly to the manner of riflling these tables.

The general object of this invention is to secure a better concentrationof the ore than is possible with tables as ordinarily rifilcd and inthis connection to provide for a scientific ore dressing-and theseparation of one mineral from another and to provide for as large ahead tonnage as is required to properly load the separating zones intowhich th table is divided.

A further object of the invention is to provide in connection with atable of this character a feed stratifying zone in which the materialis. first Stratified in vertically disposed strata in the order of thespecific gravities of the components of the material and to furtherso'riflle the table that the min eral discharged from the feedstratifying zone will be eventually discharged upon a final or mineralstratifying zone in strata disposed across the table in correspondencewith the specific gravities of the minerals.

A further object of the invention is to provide an initial rifiled zoneso constructed that it will uniformly distribute the material and feedwater and counteract, any underwashing tendency whereby fine mineralwould be carried over into the tailings before such fine mineral couldsink under the coarse mineral and be protected in its travel to th finalstratifying zone.

A further object in this connection is to provide a third, relativelylong zone in which the riflies are disposed in a direction at an angleto the direction of inclination of the table and the direction ofreciprocation of the table, these angularly disposed riflies acting tocheck the speed of the mineral and bank it up against the upper sides ofthe an-' gularly disposed riiiies in this zone to thereby compact theore bed and permit the line ma- ,terial to sink under the coarsermaterial.

Another object is to provide a fourth zone into which the angularlyriflied zone ill-S- charges, this fourth zone havingrifiles so disposedthat the mineral will move forward more rapidly than in the angularlydisposed zone and permit the freerer longitudinal movement of themineral and in this connection to provide a further riflied zone intowhich the last named zone discharges having riiiles so disposed as toagain check the speed of the mineral, these ritfies being so placed anddirected as to provide for a final separation of the minerals and tosecure a final pressure on the material which will force out the lighterparticles therefrom so that these lighter particles will be carrieddownward across the table to lower rililes and will be r orrics.

discharged upon the final stratifying zone at the proper point. g

Other objects of the invention will be more specifically stated afterthe specificarrangement of the riffies on the table have been described.

My invention is illustrated in the accorn- I I panyi'ng drawings, inwhich Figure 1 is a plan view of aconcentrat'ing table having riiilesdisposed thereon, in accordance with my invention;

Fig. 2 is a longitudinal section of the concentrating table on theline'22 of Fig; 1;

Fig. 8 is a fragmentary transverse section of the table to show thetransverse increase in the height of the riflies from the upper sideedge of the table toward the opposite side edge; and

Fig. 4 is a diagrammatic plan view to show the generalproportlons-of'rthe table and the proportions of theseveral zones.

Referring to the drawings, andv particularly to Fig. 1, lOdesignatesaconcentrating table of the usual or ordinary form, this table beingmounted for longitudinal reciprocation in any suitable manner, which'reciprocation is given to the table by any suitinstance the edge 00, ishigher than the edge 2. An end board 121s disposed at the head end ofthe table for retaining vthe material on the table. At the upper or feedside of :th6 I table, at the receiving end, is disposed the feed box 13'of any suitable construction adapted to receive the material to beconcentrated, together with feed water, and to distribute it over thereceiving end of the table at the upper side thereof. A water box 14extends the full length of the table along its upper edge by whichwashing water is discharged upon the face of the table. The surface ofthe table is a plane surface and the table is preferably of wood coveredwith linoleum to which the riflles 15 are secured in any suitablemanner. These .riffles 15 have a uniform width but taper ironi the headend of the table to the discharge end-thereof, as-will be later stated.and these riffies gradually increase in height from the upper edge ofthe table to the lower edge thereof as will K be later stated So far asdescribed, the concentrating table is of common and ordinary form and myinvention cons1sts in providing an initial stratifying zoneA, a finalclassifying or separating zone F, and providing a plurality of.rilile'zones B, O, D and E, between the initial stratifying zone and thefinal stratifying or classifying zone. The stratifying zone A isrelatively large and extends approximately somewhat more thanthreefourths of the length of the upper edge of the table andapproximately one-third of the width of the table at its head end.

The rifile zone B is disposed below the stratifying zone A and has itsriflles disposed in parallel relation to each other, to

the upper and lower edges of the table, and to the direction ofreciprocation of the table. Also disposed below the forward portion ofthe zone A and forward ofthe zone B is the zoneO in which the ri lilesare disposed at an. angle to the zone B, the rilfles extending upwardand forward, the upper rililes on this zone extending forward andtransversely across the zone A. For,- ward of the zone C thereis a zoneD having parallel ritiles, which rifiles, however,

are disposed at an angle to the riflies in the zone C and at an angle tothe longitudinal. axis of the table but at a less angle than the ritliesin zone C. This zone D at its upper end is disposed beneath the forwardnarrow portion of the zone A, and forward of the 1 zone D is a zone Ehaving riffles whichextend upward and forward at a greater angle thanthe riifles D to the longitudinal axis of the table. In other words, therifiies on zone E are disposed at an angle about the same as the rifilesin zone C. l

The line of demarcation between the riffles in zone B and those in zoneO is inclicated in the drawing by the dotted line 71, z,

. and this line is approximately parallel with of zone D is indicated bythe dotted line a, Z), this line starting about midway of the length ofthe table along its upper edge and extending down to the lower corner ofthe table at the discharge end. The riffles in zone E are about fiveinches in length in ordinary practice and terminate on the line 0, 0Kextending from a point adjacent the water box 14 to a pointon thedischarge end of the table 10 about one-fourth of the width of the tablefrom the lower corner. The riflles in zone E between the point 0! andthe point I), vof the lower corner of the table discharge at the extremeend of the table, but the rililes in zone E above the point d dischargeonto the final stratifying or classifying zone F.- Below the lowermostand foremost riffie 16 of the zones C and D is a middlings zone G inwhich the riffies run parallel to the direction of reciprocation of thetable and intersect with the lowermost riffies ofthe zone E. Along thelower edge of the table extend parallel riffles 17. These long rifiles17 are arranged to catch any mineral which may be washed out of itsproper'zone and cause the same to progress toward the discharge end ofthe table where it may be recovered for reconcentration. It is to benoted that the'ends of the ritfles in'the zone C which confront the longrifiles 17 are spaced from the uppermost of these long rifiles by aspace which may be e" wide in practice.

All of the riflles are wlde and may have a uniform width for theirentire the lines 0, (Z, Z): The uppermost riiile at the head end ofthetable is high and tapers uniformly to the discharge end of the tablewhere it is, as before stated, high. The riflies increase progressivelyin height from the uppermost ritfies of the series to the lowermostrifiies of the series, along the line hi,- these lowermost rifiies attheir head ends being, a" high. On the line a, b, the height of theriffles progressively decreases from 1:" at b to at a. the line ht' therifiles increase in height downward across the table, while on the lineab, the riffles decrease in height downward across the table. On theline between the zones D and E the riflies'have an equal height and theextremities of the rifiies of the zone E are equal in height. Of courseit is to be understood that these figures are purely illustrative as therelative heights Thus on i and spacing of the riflies may be varieddepending on the character of the ore to be treated and the tonnagerequired. The number of rifiles may also be varied. In actual practice,I use from 48 to 52 riifles depending upon the angle of the riffles inthe zone C and in ordinary practice I space the riffies 1" apart.Should, however, the spacing be more than 1 a less number of riffieswill be used. Thus, for instance, the standard riflie which I haveheretofore referred to is -3 high at the head end and tapers to -g highat the discharge end. This rifile is suited to an ore containing 20 to40% mineral, but in treating a 5% ore a riflle depth of 3 1' at the headend and at the tall end,

' angle tothe riffles of zone B and theriffles of zones Dand E as beingdisposed at certain angles, I wish it understood that these angles willbe varied depending upon the character of the ore, as will be more fullybroughtout later. A

No means for separating and stratifying ore equals a smooth agitatedsurface upon which the ore is disposed. It is for this reason that Ihave provided an initial stratifying zone A having a relatively largearea. "On this stratifyingzone, themineral is stratified according toits specific gravity before it enters onto either the "rifile zone l3 orthe riffie zone C. In this zone A several actions take place. The heavybottom stratum of ore which receives the impulse of the longitudinalthrust caused by light gangue from the zone A passes into zone B and thelongitudinally extending parallel rifiies of zone B-distribute thematerial and the feed water uniformly over that zone and thereby preventany undue washing tendency that would tend 'tocarry the fine mineralover into the tailings before such fine mineral could sink under thecoarser mineral and be protected on its travel to the mineralstratifying zone F.

It will be understood that the stratifying zone Ais for the purpose ofpermitting all mineral to sink and engage the smooth surface and tobecome stratified in the order of itsspecific gravities. theheaviermineral moving forward and finding 'lodgment against theuppermost rifiie of zone 0. Meanwhile the lighter gangue and mineralhave been carried. over into zone B, evenly distributed in this zone,and when the mineral reaches the first angular 'riffie in zone C. theseparation of one'mineral from an-' other commences and at the same timethe separation of all minerals from the gangue commerces- Thelongitudinal movement of the table forces the mineral particles for-,

ward against the angular riffiesin zone C with considerable forceand-"inasmuch as these angular riffies impede the forward progress ofthe mineral particles, these angular riffies cause each, mineral bed topack against the riflie just below, which has the effect of forcing outall particles of lighter specific gravity than the mineral properlyaccompanying or corresponding to the space above such riflle and thisprevents the wash water coming from the wash box 14 from passing throughthe mineral bed. with adetrimental effect which it-would do were theirifflesin zone C disposed parallel to the longitudinal axis of theconcentrating tablef Y The angularity of the riflies in zonewC,

which angularity may be anything from 1} per foot to 5 inches per foot,depending on the character of ore treated, is for the purpose ofchecking the speed of the min eral and causing it to bankagainst theup-' per side of the rifile, thus permitting the finer mineral tosinkunder the coarser min.- eral and force out all sihcious particles.-

The angularity of the .riflies in zone D may also be varied to meet thedifferent conditions depending upon the. ores being treated. The objectof having the "rifiies in zone D at a less angle thanthe riffies in zoneC is that this permits the mineral mass to move more rapidly andallowsthe riffies in zone C to feed onto zone'D more readily.

.Zone Ehas riffies init of greater angularity' than the rifiies in zoneD, the riflies in zone E checking the speed of forwardmovement of themineraland causes a final washing and discharge onto the mineralstratifying zone F. i

. I have stated before that the mineral par-' ticles are forced againstthe riffles in zone C with considerable force and-"are packed by therifiies thus forcing out all particles of lighter specific gravity thanbelongs in the particular space betweentwonriffles. Another effect alsotakes place in zonetC and also in zone E, this effectxbeing based uponthe action of a natural law which may be termed the law of selection. If.dry granular material is placed upon a plane agitated surface, theparticles of material will range themselves as follows :--The coarserparticles will rise to the top-and the finer particles will sink to thebottom, with out respect to the relative specific gravities This, asabove noted, is

specific gravity as the coarser particles from sinking downwardthrough'the mineral bed of fine mineral.

to the deck: surface of the table and being thereby protected from'theheavy flow of wash water throughout zone C :and to less degree inzonesID and E. This action 'is not active to any appreciable extent, inconcentrators having: deep longitudinally extending rifiies, that isriffles which are parallel to the direction of movement of the table,for the reasonthatthe bed of mineral is too light and buoyantand themineral is notsufficientlyi packed; The Wash water penetrates themineral beds between the longitudinally extending riffles and washes outthe fines'and there is a resultant lossv F or example, in an ordinary.16 foot table.

concentrating an ore ground tosa-y'a 20' mesh screen and havinglongitudinally extending rii'fles on itssurfaces, the time required forthe .ore to be passed from end to end ofthe table is about one minuteand five seconds. Assuming that the riffles in zone C areidisposed at anangle of15 t0 the direction of movement of the table, then these angular.r'iiiles .in zone (3- reduce the speed of the mineral one-sixth andfurther act to'compr ess the bed of mineral one-sixth above itsnormalstate where the ore is moving between longitudinallyextending rifl'lesand this compression in zones C, D and E will be in direct'proportion tothe angles in the rifliesin these zones It will be seen, therefore, thatthe action of the rifi'les in zone C and to aless degree in zones D andproperly occupying any particular space between two rlflies.

The angle of the riflies in'zone E is for the purpose ofefi'ecting finalmineral separation,-.but-I do not wish to be limited to the 'use oft'his zone E as the use of this zone is necessary only where ores arebeing concentrated having a heavy gangue, which so closely approaches inspecific gravity, the specific gravity of the mineral,- that a lastfinal pressure is necessary to force out the lighter particles whetherthey are gue or mineral, so that these lighter particles may flowdownward across thetable, find, their proper bed, and may enter thefinal classifying or stratifying zone E at a lower point and each at itsproper place. e In the classifying zone F, the minerals are arranged inlongitudinally extending lines .or stratas lying side by side in theorder of their specific gravities, the heaviest mineral being of courseat the upper portion of the zone F and the lightest mineral at thebottom of the zone. It will be seen that ma es;

Whereas in' zone A the strata of mineral are superimposed in the orderof their relative specific gravities, in zone F the strata are; notsuperimposed, but are disposed or an ranged in what may be termed ahorizontal relation instead of a vertical relation. The,

riflles which retain the relatively heavy particles of gangueitwill beseen discharge'at the-end of the table and .=not upon the classifyingzone "F except,-of course, those rela tively-long riiileslTpreviouslyreferred to. whichdischarge at the end of-the table. 1

The'zone G is a middlingf zonegand operates in conjunction. with thelong vrifiles at the bottom of the deck; Material f'getsgintothis-zone Gby flowing over the-last rifile of: zone C. The ,end'anglesactfjto'passthe lighter particlesovei' the top of the rifles to the next lowerandtendtoplate all particles in their relative order ofspecificgravityso that the gangue may be more. easily cut out.

It is also necessary to take into consideraand by providing. a large'mineral classify ing zone onto which the riffles .discharge, the

riiiles entering this final classifying zone in a direction sufficientlytransverse to the longitu'dinalthrust of'the'table as to deliver thevarious mineral strata from the table without unduly mixing one strataor group with the other strata or group next lower in the zone and nextlighter in'specific gravity.

I havefound by experiment that there is no definite angle at whichtherifilesin zones C, D and E must be placed forthe reason that no twoores are exactly similar in constitution. Someores can be crushed intocoarseriparticles than others and can be dressed in that state, Whereasother ores re quire finer crushing to free themineral from the gangueand still other ores require a much finer. crushing not only. to freethe mineral from the gangue but to free one mineral from the other.Each-ore to. be treated,'therefore, is a problem peculiar to, itself.The angularity of the rii'rles-C, D and E must therefore'be adjusted tothe various ores as accurately as practical knowledge and experiencerender possible.

For instance, a coarsely crushed ore, the mineral of which may have-thesize of 10 mesh,.will not pack as firmly against a there will be avariation of riffle angle in zones and E asv requirements may indicate.Some mlneral and gangue are so near alike in their specific gravitiesthat a relatlvelygreat angle in zone C Wlll be necessary in order tobank the mineral, check its advance along the riflies and force thegangue to rise to the top and pass over to theneXt rifile below.Conversely if there is a wide difference in the specific gravities ofthemineral and the gangue,rthen the riffles in zone C may be'disposed ata less angle which will be suflicient to cause the gangue and themineral to be washed apart and sufficient to clean the mineral. In thiscase, of course, the gangue and mineralwill travel faster toward thedischarge end of the table and will be less compacted than where theriflles in zone C, are disposed at a relatively great angle. The samerule applies to the riffles in zone E. Some mineral will beso thoroughlycleaned when it enters the zone E that only a very low angle of theriflles in zone E will be required whileanother mineral may require avery high angle owing to the presence of a very heavy gangue. Under allcircumstances, however, thelriffles are so I designed in accordance withmy invention as mineral stratifying:

to cause the banking or compacting of the mineral by checking its traveland, furthermore, by causing the wash water to wash the gangue backtoward the head of the. table which makes the gangue line run well downtoward the discharge side of zone C.

IVhile I, of course, do not wish to be limited to any specificdimensions, I have illustrated a concentrating table having about thefollowing proportions The table shown in Fig. 1 is supposed to be 15feet, 8 inches over all, the upper end of the line w-b 1s supposed to beabout 8 feet from the discharge end of the table, while the upper end ofthe line 0cl is supposed to be 4 feet, 9 inches from the end of thetable. Thetable is 5 feet, 6 inches wide at its discharge end and thelength of the zone B from the head of the table to the line 711 i isabout2 feet, 5 inches. l/Vith this proportion of parts, the

distance between it and a would be-bjfeet,

while the'distance from 11 to the line wb along the riffle in zone Uextendingfrom the point i would be 8 feet. .I merely glve thesedimensions .in order that the pro- Q portions ,of the feed stratifyingzone, the

zone and the several zones B, (I, D and may be understood.

I am aware that it has been proposed to table. I am not aware that ithas been proposed to provide a relatively large stratifying zone for thepurpose of disposing the ifferent component parts of the material invertical strata corresponding to the relative specific gravities of thecomponents, and before thematerial passes on to the longitudinal rifflesof zone B.

In some forms of concentrator,:inclined rifiles are provided but theseriffles are relatively wide apart, that is, the riffles in the inclinedzone are wider apartthan the longitudinal riffles. This is notadvantageous for thereason that the wider the space between the rifiies,the greater is the cascade of water over the riffle above the space. Nowthe material 'on the table or deck seeks to have alevel surface and in arelatively wide space the material above thelrilfle may not extend abovethe base of the riflle next above in whichv case the wash water willpour'over the riflle next above with a heavy washing effect. This is thecase also where the riffles are longitudinal and not disposedat an angleto the line of reciprocation of the table. Now

if a short diagonal zone is interposed be tween the longitudinalriffles, withrelatively deep riflles and wide spacing, thistendency 7 ofthe wash water to cascade over .the riffles is reduced and there is anincreased tendency of the washwater to flow down the channel and toproduce a strong washingeffect rear H very short, the cleaning effect isproduced by the strong back wash. Nere the spacings of the diagonalriflies and the height of said diagonal riflles such that the materialwould fill the space between the ri'lfles when operating at an ordinarytable inclination, there would be a reduction of. this tendency to distribute the mineral bed and the washing effect would be confined to thesurface of the material.

length of the diagonal zone and under these conditions, were the spacesbetween the riflles 1 filled.with arelatively solid compacted mass ofmineral, there islittle orno back wash ng V In that case there would bea .banking effect just in proportion ,to the effect as the riffles aresubmergediin the bed v of material and the washing tendency istransversely across the deck and is not influenced by the diagonalrifilesf d In my system of riffling. the rifiles are uniformly spacedfromv each. other, whereas if the rifile channels arewider inthe zone Cthan intthe other zon'es, the packing" or compacting action of theinclined riflles'will that point, where there is not enough ma mineralscollected inthesev lower beds and ,where, therefore, ,a longer actionmust be delicate separation.

p be reduced and the fines will be liable to be washed out.

In actual practice I have proven that there is no back 'washing'effectin my system of rifitling, by pouring asmall amount of black oil on thewater at'the upper side of the zone C and I find that as the oil travelstoward the lower side, the oil makes a small advance toward thedischarge end of the table as far as the riflles are filled, but belowon the mineral bed.

Again in my system of riffling less that 30% of the riffied suface haslongitudinally extending riflies, while 70% has inclined riflles. Thusduring 70% ofthe travel of the ore over the riflles', the ore beds arebeing compressed and the lighter particles of gangue, etc., are beingsqueezed out and carried away.

Again it will be noted that in my system, the uppermost riflle inizone Cis relatively one-third shorter thanthat little of zone C which extendsfrom the lowermost rifile of zone B and that the lengths of the rifiiesin zone C increase progressively downward across the table. Thus in theupper mineral beds composed of very heavy minerals, the 1 compressiveaction is .of relatively shorter duration than in the lower beds wherethe light minerals collect and where the gangue approaches most nearly'the weight of the provided for in order to secure this more The line 0-Zdefining the discharge ends of the riflies is disposed at an angleacross the zone F in order to cause the wash water to wash backward anddownward.

It will be understood that the zone D is absolutely essential to theproper working of zone C; Zone D is set. at a low angle in order to movethe bed rapidly from the zone C owingto the rifiies having less depththan "the rifllesin zone'G. This allows zone C' to discharge its leadfreely. Zone E is very essentialwhere ores are treated having a MheavyfganguejLOnly with ores of an extremely light gangue and a veryheavy min.-

eral. do I contemplate using a relatively low 1 angle in zone B. On allores of heavy gangue fIiwill use a high The zone Bis relat v'ely'of lessimportance than any zone of riflie. I

The object of these rifiies is to form beds my system, yet it is highlyessential to proper operation of the remainder of the system. 'Zone 0 isthe absolutely vital zone but each of the zones has an importantspecific function. I p p The banking and cleaning effect in" my systemis due to the long angular zoneIC in conjunction with the angularriffles, the wash water flowing over the top of the riffles and over thebeds of ore and acting directly on the top of the particles, there beingno chance for the water to cascade over the top of the space, becausethe space or channels between the riflies are full to the top of theriffles and, therefore, all wash is transverse. angle of deckinclination may, of course, be changed depending upon the ore beingtreated, for instance, on lead carbonates, I use an angle of about t toper foot.

It will be seen that in its complete formmy system of riffiing includesthe use of six riflle zones A, B, G, D, E, F. Eachzone has its separateand distinct function to perform, and at the same time, is dependentupon the The '80 correct action of all the zones acting conjointly,thereby forming a system of riflling, in which no. single zone iscapable of producing results that equal the results obtained by the useof all zones working in harmony.

The initial zone A is the zone which receives-the feed, and is formed bythe top rifHeQ In this zone'are placed, one or more short rifiies,spaced 8 to 10 inches apart,.so arranged as to form mineral beds; .Theserities have less length than the feed box' with a depth nominally thesame as the top of stratified mineral and also to hold the mineral atthetop of the riflie system and prevent it passing with the pulp down'tothe middle of the table, as would occur. very largely were these riiflesnot'used. The riffle which forms this zone does not have holdingcapacity to prevent a large amount of the.

mineral from entering zone B.

The ob ect of zone A is to trap out and stratify the mineral ,into'vertical strata,

which is progressed forwardand the lighter strata, shaved off to a'lowerposition, wlthout disturbing or breaking up the various strata.-

as they pass through the various zones following' Zone intothe followingangular zone C, andbe fore-the mineral can pass far down in zone 1 B. Atthis, point-two objects are sought: 1st

to stratify and, 2nd to retain all mineral as high up in the rifllesystem as possible, which B is ashort longitudinal zone, and is I ,soarranged for the purpose of forming a light buoyant bed ofmaterial, inwhich the mineral can settle quickly and be progressed in-th'e finalefiort,prevents a heavy mineral f 7 from having to cross under the lineof'lighter V tions, the tendency of the clean mineral is,

' ZOIIGS.

form of the mineral beds, these fines are protected from the cross washand follow this bed to the point of delivery. This action is due to thenatural law of selection.

Zone Cis arranged angular, for the purpose of forming a compact slowmoving mineral bed, which receives the Stratified mineral from zones Aand Band progresses the same in a compact form, constantly squeezing outall the lighter particles, andcon'stantly concentrates the mineral asit: advances, and as the riifle depth grows less, the top strata aresheared over to a lower position in'the transverse angle of the table;this action continues throughout the length of this zone.

The concentration made in zones AB- C, are only part of the final effortof all All material fromzone C passes to zone D which has lessangularity than zone C. The object of this is to progress the materialat a more rapid rate,and to produce more buoyancy to the mineral bed,while the top strata are being sheared over to a lower position, beforeentering the final riflle zone E, which has its greater angularity thanany of the preceding zones.

The object of this, is to form a compact mineral mass such that no lightparticles can remain in the stratum notcomposedof particles of similarspecific gravity. In other words, particles of dissimilar gravitiescannot occupy the same stratum in zone E. i 7

All the mineral is completely concentrated and accurately stratified inthe combination of riffle zones, and delivered into zone F, in cleanlateral strata and quickly discharged from the table, before it ispossible for v one stratum to climb another stratum due to the smoothsurface and transverse angle of the table, together with the washingeffect of the dressing water, as, under these condifor the heavy stratumto pass under the next lighter'stratum,'a nd therefore the overlap be-Vtween each mineral stratum is proportionate to the length'of'the smoothzone, and the time required for the mineral to pass off the smooth zone.7 r I V Zones E and C are both flexible zones, that is, their'angularity governed by the character of the material which they arerequired A to treat, both as regards the nature of the ore, as wellv asthe texture, or mesh to which the 1 table feed is crushed. In otherwords, the rifile system isadjusted to the requirements the old riffle'system, wherein an attempt is of the ore, and not'an arbitrary system,like thoroughly cleaned passes into made to makeithe ore fit theri-iile' system, which is the direct cause of so many failures to themany different elassesof ores.

The angularity of zone E depends especially upon the relative gravitiesof the various particles ofboth the mineral and governed by the textureormesh' of the table feed, in fact this system is arranged to meet thespecial requirements 'of the ore in every case. V

Itwill be'understood that the deck-plane of my concentrating table isall in one "plane with the entire surface from the waterbox to the loweredge of the" table lying at the same lateral inclination. It will alsobe seen that the zone A is approximately triangular 1n form, being largeat the-head endand relatively wide, and very narrow where it joins zoneF so that the zone F would be 'entirely cut off from zone A at the point0 were it not for the water box and in order I gangue, while theangularity of zone C 1s' v to have the riflletips disposed for cleaning(in case of oxidized minerals'cementing to the deck when the table isstopped, which is a commondifliculty). This difficulty makes itdesirable to keep the riifie tips all in the clear. Therefore, theriffie tip of the uppermost riflie does not touch the water box but atthis point only clean, heavy mineral 7 smooth surface above, so that infact zone A r I is a separate and closed zone and is not oined in actionto zone F, in other words only the heaviest mineral which has beendirectly from the zone A. i

The action of the material in zone A isas follows The feed water andpulp pass across this zone toward the riflle zones B and C, with aboutthree fourt'hs' of the feed of the pulp passing toward zone B.

the zone F Immediately'upon this smooth surface of the zone A, alltheparticles are segregated and pass laterally down the inclined face ofthe zone A rapidly unt lthe uppermost bounda 'y riffle is reached, Here,the material is banked and formed into a bed some six or seven incheswide, and it is in this bed that the real Stratification takes place.This bed follows the upper riffie or boundary riffle with a varyingwidthto about one inch at the point c. Beyond the end of the feed'box l3thereis no material in zone A exceptthat portion banked against theboundaryrifiie, and as "the table motionis su'ioothgand the mineral bedis advanced without disturbing the strata of thisbed and'as therilfledepth is less as the bed advances, the top strata; of this rifiiebed. aresheared over the boundary ,riflle into zones Cand D, it beingnoted that the inclinedrimes of zones C inter- Y i riflies in the rifllezones C and D and E proother class or spread out so that the operatormay see better how to separate the classes of mineral into separatelaunders. The angular boundary of zone A andthe angular duce separatingresults through the action A of compressing the mineral beds, squeezingeffect.

out the lighter particles, and causing these lighter particles to shearover the rifiles as the mass is progressed forward along rifHes whichdecrease in height and which are placed on an inclined surface. The onlyzone which does not form a compressed bed is the zone B, Where theriflles extend parallel to the direction of motion of the table. Thiszone B forms a light and buoyant bed of material and only acts to sinkall mineral quickly so that it may be later acted upon by the squeezingand compression action in zone C. It is also to be understood that mytable is to be reciprocated by that" form of mechanism known as thetoggle motion, which is quite commonly used in concentrating tables,which produces the same progressive movement as the bed of materialmoves forward and does not set up a remixing action as is produced bymechanism such as that used to produce a bumping motion. This commonlyused toggle motion produces the forward movement of the material on thetable by moving the table forward at such a ratethat all the particlesfollow the surface. This stroke starts slowlyand stops slowly withoutimpact or disturbance of the mineral bed, and has its greatest velocitynear mid-stroke. The return stroke is similar, except that its rate ofspeed is faster and the deck surface, therefore, is slipped under thematerial without disturbance or stirring This stroke is usually about %7long and rarely over 1 long, so that this action can easily take placewithin the space between the angular rifiles, which are spaced about Iapart and without any disturbance of the strata which may be formed fromagitation by this motion. In the angular zone C' where the mineral bedsare formed by compression, the angularly disposed riifles permit thefine mineral to sink and pass under the coarser minerals and in wettable concentration specific gravity acts to select the particles oflike gravity so that only the heavy particles can enter a stratum oflike gravity composed of coarser particles. This means that fine leadwill enter the coarse lead stratum, fine iron will enter the ironstratum, and the fine zinc will enter the zinc stratum, and that thefine gangue particles of the .heaviestclass will enter the heavy ganguestratum on top of the zinc stratum. 7'

Vertical stratification will place the minerals in the order named insuch arrangement or stratification, and thus if the mass is compressedinto a compact, heavy bed, such as is produced by the inclined rifiles Gand D ring, concentrating table having no lateral component in. itsmovement and having its upper surface disposed entirely in one plane,said table having a relatively large, smooth, initial stratifying zoneat the'head'end of the table, the lower boundary of this stratifyingzone extending upward and forward at an inclination to the direction ofmovement of the table, a relatively large,

smooth, flat, classifying zone at the discharge end of the table andextending transversely thereof from the upper sideitoward the lower sideof the table, and a zone disposed between the stratifying zone andclassifying zones and separating them from i each other having rifflesinclined upward and toward the discharge end of the table and at such anangle to the line of motion of the table as to offer material resistanceto the progress of the material, the channels defined by saidinclined'zone of riffies all discharging upon the final classifyingzone, and the uppermost rifile forming an upwardly inclined boundary tothe lower edge of the stratifying zone against which mineral in thestratifying zone will bank.

2. A longitudinally horizontal but transversely inclined concentratingtable having longitudinally reciprocating movement without lateralcomponent and having its upper surface disposed in one plane, said tablehaving a relatively large, smooth, inifying zone at the discharge end ofthe table and extending transversely thereof, and a zone disposedbetween the stratifying and classifying zones and separating the onefrom the other and having rifiles inclined upward and towardthedischarge end of the table and extending transversely to thestratifying zone, the uppermost riflie forming the uppermost boundaryofsaid riffled zone extending upward and forward at an inclination tothe lineof motion of the table and forming the lower boundary of thestratifying zone, the channels defined by said inclined riffles alldischarging upon the forward classifying zone, the ends of said riffiesbeing disposed in a line extending downward and forward toward thedischarge end of the table.

3. A transversely inclined concentrating table having longitudinalreciprocation without any lateral component, said table having arelatively large, smooth, initial stratifying zone at the head end'of'the table, a relatively large, smooth, fiat classifying zone at thedischarge end, and a pinrality of zones disposed between the stratifyingand classifying zones having uniformly spacedrilfles inclined upward andtoward the discharge end of the table and extending transversely to thestratifying zone, the riflies in the several intermediate zones havingdifferent relative angular relations to each other, the channels definedby said inclined rifiles discharging upon the. final classifying zone,said inclined. rifiles being disposed at such aninclination to the lineof motion of thetable as to offer material resistance to the progress ofthe material being concentrated. a p

4. A longitudinally horizontal but transversely inclined concentratingtable having its upper face disposed in one plane and havinglongitudinal reciprocation with no lateral component, said table havinga relatively large, smooth, initial stratifying zone extending from thehead end of the table along the upper margin thereof and beingrelatively wide at the head end of the table and narrowing toward thedischarge end thereof, the table also having a relatively large, smooth,flat, classifying zone at the discharge end of the table extendingdownward from the upper margin thereof, and an intermediate zoneextending downward from the stratifying zone to the lower edge of thetable, and having riifles extending at an angle to the line of movementof the table and all discharging upon the final classifying .zone at anangle upward-and. toward the discharge end of the table, th rifflesbeing uniformly spaced apart for their entire length, and the angle ofthe riifles relative to the line of motion of the table being such as tooffer-material resistance to theprogress of the material beingconcentrated whereby to cause compression of the mineral beds formedbetween said rifiles and squeeze out the lighter particles therefrom,said uppermost, inclined.

stratifying zone from the final classifying.

zone.

5, A longitudinally horizontal transversely inclined concentrating tablehaving a relatively large smooth initial stratifying zone extending fromthe head end of the table longitudinally along the upper margin thereofand a final classifying zone at the discharge end of the table extendingdownward from the upper margin thereof toward the lower margin thereof,the table'at its head end below the stratifying zone being formed with-a zone having parallel uniformly zone from the classifying zone, thedis-, I

charge ends of the'channels between. the

'riifles discharging upon theclassifying zone and being disposed on aline extending downward and; toward the discharge end of the table andextending transversely across the lower portion of the classifying zone,the lowermost inclined riflies extending to the extremity of the table.

inclined concentrating table having longitudinal reciprocation with nolateral component having at its head end a relatively large smoothinitial stratifying zone extending longitudinally along the upper-marginof the table, the lower boundary of the stratifying zone extendingupward and toward the discharge end of the table nearly to the uppermargin of the table, an approximately'triangular classifying zonerelatively large in area disposed at the discharge end of the table andextending from the forward end of the stratifying zone to thedischargeend of the table, the base of the trianglebeing at the upperedge of the 1 O 0 6. A longitudinally horizontal transversely table andthe apex of the triangle extending ing parallel to thefline of movementof the table and forward of this zone with a zone having uniformlyspaced riffles extending upward and toward the discharge end of thetable at such an inclination to the line of motion of the table as tooffer material resistance to the progress of the materialheingconcentrated, said zone defining the lower forward boundary of thestratifying zone and said rifiles terminating on a line extendingdownward and toward the' discharge end of the table and defining thelower boundary of the classifying zone, the lowermost rifiles 'ofjtheupwardly inclined riffies extending to the extremity of the table. a

7. A longitudinally horizontal transversely inclined concentrating tablehaving longitudinal reciprocation but no lateral component having at itshead end a relatively.

' large smooth initial stratifying zone extending longitudinally alongthe upper edge" ofthe margin of thetable, the lower boundary of thestratifying zone extending upward and toward the discharge end of thetable nearly to the upper -margin' of the table, an approximatelytriangular classifying zone relatively large in area disposed at thedischarge end of the table and extending from the forward end of thestratifying zone to the discharge end of the table,'

7 the apex of the triangle being toward the lower edge of the table, thetable being provided below the head end of the stratifying zone with azone having longitudinally extending riffies parallel to the sides ofthe table and for-ward of this zone with a zone having rifiies extendingupward and toward the discharge end of the table, said zone defining thelower forward boundary of the v the line of motion being such as willmaterially resist the forward progress of the material beingconcentrated.

8. A transversely inclined concentrating table having longitudinalreciprocation with no'lateralcomponent and having a feed box and a waterbox extending along its upper margin, the table having a relativelylarge feed stratifying zone at its head end and extending toward thedischarge end of the table and a relatively large classifying zone atthe discharge end of the table and extending downward from the uppermargin thereof, the table below the rear end of the stratifying zonehaving a plurality of riffies extending parallel to each other and tothe line of reciprocation of the table, the table forward of this lastnamed zone being provided with riffles extending upward and toward thedischarge end at an angle tending transversely across it, a third riffiezone disposed in advance of the last named riffie zone and havingriflles extending up rifile'zone having rifl'les'extending upward" andtoward the discharge end of the table at a greater angle than'in thesecond named:

riflie zone, the discharge'ends of the Chan-- nels defined by said lastnamed-rifiles being disposed on a line toward the discharge end of thetable at an angle to the line of reciprocation and from the upper marginof thetable to the discharge end thereof and intersecting said dischargeend at a point. above the lower edge of thetable. 1

9. A transversely inclined concentrating table having longitudinalreciprocation with no lateral component and havinga feed box and a waterbox extending along its, upper margin for its entire length, said tablehaving a flat smooth relatively large feed stratifying zone extendingalong the upper mar gin of the table from the head endtoward thedischarge endand having a flat smooth relatively large classifying zoneatthe dis' charge end and extending downward from the upper margin ofthe table nearly to the lower margin thereof, the table below the headend of the stratifying zone having a zone formed with longitudinallyextending riflies parallel to the'line of motion of the table, saidriflies at the lower edge of the table extending longitudinally the fulllength of the table, thetable in advance of the longitudinally rifiiedzone being formed with a second riflied zone having upwardly andforwardly inclined uniformly spaced riflles extending at'a predeterminedinclination to the line of motion of-the table and transversely of thestratifying zone, a third successively disposedriflied zone havingriffies extending at a less inclination than in the second riflied zoneand a fourth relatively short riffled zone having riffies disedge of thetable, the line of juncture bea tween the riffies of the second namedriffled zone and of the third named riflied zone ex tending downward andforward from the upper margin of the table to its lower forward cornerat a greater angle than the angle of the line bounding the lower end ofthe classifying zone. i

10. A longitudinally horizontal trans c,

clined riffles discharging upon the final classifying zone, theuppermost riffie of the riffied zone forming the boundary of the lowermargin of the stratifying zone, the rifiies 'being uniformly spacedalong their entire extent and uniformly tapering from the head end tothe discharge end of the riffles, but said riflies at the beginning ofthe inclined riflie zone progressively increasing in height from theupper margin of the table to its lower margin.

11. A laterally inclined concentrating table having longitudinalreciprocation with no lateral component, the table being formed at itshead end and adjacent its highest margin with a longitudinally extendingstratifying zone and below this zone with a longitudinal rifiied zone,the riflies for a portion of their length extending upward and towardthe discharge end of the table at an angle to the line of motion of thetable and forming an upwardly inclined boundary to the stratifying zone,the rilfies forming the boundary of this zone extending unbrokenly fromthe head endvof thezone to the discharge end thereof, means fordischarging pulp upon the stratifying zone at the head end thereofandrcausing the pulp to flow transversely of the table, and means fordischarging wash water upon the table along the upper margin thereof andin a direction transverse to the longitudinalaxis of the table. I

12. A reciprocating laterally inclined concentrating table moving in aright line direction with no lateral component, having means forsupplying wash water along the upper margin of the table, and initialstratifylng zone, a final mineral classlfylng zone,

and riflies extending longitudinally of the table and defining orechannels, said riflies being uniformly spaced but being so disposed fora portion of the length of the table as to resist the forward movementof the ore along said channels to thereby compact the ore beds in thechannels and squeeze out relatively light particles,the discharge endsof the channels being so formed as to exert a final compressing actionon the ore in said channels just previous to its discharge upon thefinal classifying zone.

In testimony whereof I hereunto afiix my signature in the presence oftwo witnesses.

BENJAMIN A, HUGHES.

Witnesses MIKE WOLF, HENRY ELLIS.

